The only difference between def:cpf and def:rcpf is that the latter does not require \(\lim _{x \rightarrow \infty } \phi (x) = 0\) ; a relaxed convex loss function may take (arbitrarily large magnitude) negative values. [1]} exploit this flexibility by proposing the following simple potential function, which they call the “unhinged loss”:
\(\phi ^\ast (z) = 1 - z.\) 
